If you're building up a set of road wheels and want the lightest rotor SRAM currently makes, the Paceline X sits at the top of their road disc lineup. It uses the same Paceline brake track SRAM developed for quiet, smooth road braking, but pairs it with a lighter aluminum spider than the standard Paceline — enough to bring a 160mm rotor down to around 130 grams. It's a two-piece Centerlock-only design, available in 140mm or 160mm.

The pitch from SRAM is straightforward: their smoothest and quietest brake track paired with the lightest aluminum carrier they've built. The steel braking track handles the friction and heat while the aluminum spider keeps rotational mass low — the part of the wheel where grams matter most because you're accelerating and decelerating that mass every time you touch the brakes. The rounded edge profile on the outer track also cuts down on the razor-blade sharpness of a fresh rotor, which is a small quality-of-life thing when you're swapping wheels or wrestling a bike into a car.

One spec worth flagging before you order: the Paceline X has a minimum thickness of 1.7mm printed on the rotor, which is thicker than SRAM's older Centerline rotors that used a 1.55mm wear limit. Fresh rotors measure around 1.85mm, so you have a smaller wear window than you might be used to. Keep a caliper or rotor gauge on hand and check thickness at service intervals — this rotor doesn't give you as much material to burn through before replacement.... Read More